A stable isotope geochemist, who likes mud, lakes and oceans

About me and my research

Hello, I am a stable isotope geochemist interested in biogeochemical cycling and climate change. Whether this be over the past c. 10,000 years (the Holocene) or in the future, my work has focused on the use of diatoms (unicellular, siliceous algae) which are ubiquitous and preserve well in both ocean and lake sediments. Through identifying diatoms it is possible to reconstruct environmental change through qualitative or quantitative means.

Through the isolation of these organisms in sediments it is possible to analyse their stable isotope geochemistry (e.g. δ¹⁸O, δ³⁰Si) to reconstruct variations in climate and productivity. When used in tandem with other proxy records, detailed palaeoreconstructions can be derived in order to appreciate how our climate has been forced in the past and estimate the consequences of future anthropogenic pressures on our climate.

More recently, my work has focused on understanding in more detail the modern biogeochemical cycling of both carbon and silicon, through stable isotope techniques (e.g. δ¹³C, δ³⁰Si). This work is conducted at the Centre for Environmental Geochemistry. Both the silicon and carbon cycles are intimately linked through silicate weathering processes and the oceanic biological pump, as they both drawdown atmospheric CO₂. As a result (and although not widely acknowledged) the silicon cycle has an important impact upon the future sequestration and export of CO₂ from the atmosphere.

With increasing anthropogenic pressures and the projected continuation of increased atmospheric CO₂ concentrations, a detailed understanding of this important biogeochemical pump is ever more crucial. While a large body of work has centred on Rainforest deforestation and what this means in the loss of future carbon capture potential, little work has (until now) centred on regions of productivity hotspots, such as wetland systems (e.g. mangroves). Here carbon drawdown potential is much higher due to their high species colonisation and turnover (commonly termed Blue Carbon). However, now too these ecosystems are suffering increased deforestation and pressures for shrimp farming and biofuels. Their demise and the potential loss of these carbon stores in future decades could have a very significant effect upon the mitigation of climate change as a whole.